Soo Locks Set to Reopen March 25, Launching 2026 Great Lakes Shipping Season

The U.S. Army Corps of Engineers will reopen the Poe Lock to all marine traffic at 12:01 a.m. EST on March 25, marking the official start of the 2026 Great Lakes shipping season. For the Great Lakes freighter fleet, it is the starting gun that ends months of enforced stillness.

The Soo Locks, on the St. Marys River between Michigan's Upper Peninsula and Ontario, were first opened in 1855. They remain the only navigational link connecting Lake Superior to the lower Great Lakes, and no ship can move iron ore, coal, limestone, or grain between the two systems without passing through them. More than 4,500 vessels carrying up to 80 million tons of cargo maneuver through the locks annually.

The scene in the Wisconsin ports this week tells the story of a fleet at rest, soon to stir. At Fraser Shipyards in Superior, several vessels have spent the winter in layup, sitting quietly at the docks while crews completed maintenance work ashore. Two of the largest freighters on the lakes are also waiting nearby: the Indiana Harbor, a diesel-powered lake freighter owned and operated by the American Steamship Company, was built in 1979 at Bay Shipbuilding Company in Sturgeon Bay, Wisconsin. It sits at the Lakehead Pipeline dock in Superior. The Burns Harbor is also owned and operated by the American Steamship Company and was built in 1980 at Bay Shipbuilding Company in Sturgeon Bay. It has been laid up at Elevator M, also in Superior. Both are 1,000-footers, the largest class of vessel that can transit the Poe Lock.

The Duluth-area maritime community has been tracking the winter layup season closely, with local observers dubbing the dormant fleet the "Sleeping Giants" as they wait for the locks to reopen. Shipping traffic in the Twin Ports is expected to resume shortly after the locks reopen. An aerial video circulating among ship-spotting enthusiasts shows the Wisconsin yards from above, tracing a route from Fraser Shipyards through the Superior waterfront before closing with scenes from Bay Shipbuilding in Sturgeon Bay, where additional vessels have wintered over.

Soo Locks Operations Manager LeighAnn Ryckeghem said the winter closure period "is essential for conducting critical inspections, repairs and maintenance on our aging infrastructure," adding that "the reliability of Great Lakes navigation and the momentum of the American industrial supply chain depend on getting this work done."

The Soo Locks have been closed for the winter since Jan. 15. The MacArthur Lock will remain closed until its needed repairs are completed, leaving the Poe Lock as the sole passage for the season's opening traffic. The March 25 reopening date is typical for the annual shipping season.

The park and viewing platform at Sault Ste. Marie will open at 11:30 p.m. on March 24 to allow visitors to watch the first ship from the viewing platform, and the Visitor Center will host its annual open house from 9 a.m. until 3 p.m. on March 25. For those unable to attend in person, the Detroit District will host a Facebook Live event at the U.S. Army Corps of Engineers Detroit District page starting at 11:55 p.m. on March 24.